A composition is composed of a hydrophobically modified polyacetal-polyether (HM-PAPE) or comb hydrophobically modified polyacetal-polyether (comb HM-PAPE) and a viscosity suppressing agent of cyclodextrins or derivatives thereof. A method for improving the pumpability and pourability of aqueous solutions of HM-PAPE or comb HM-PAPE is provided by admixing a cyclodextrin with the HM-PAPE or comb HM-PAPE to form a complex of the cyclodextrin and HM-PAPE or comb HM-PAPE where the viscosity of the HM-PAPE or comb HM-PAPE is suppressed and adding the complexed admixture to an aqueous system containing a water-insoluble polymer wherein the cyclodextrin is decomplexed and the HM-PAPE or comb HM-PAPE becomes an effective thickener. An example of the uses for this composition and method is in film forming coatings such as latex paints.